#1078 Customization of mail sent by request notifications

[FreePath]

When a request is changed, or when the Request Processor generates a notificaton, an email may be sent to a user. The text and subject of the mail are hardcoded and cannot be modified.
But, for some usage scenario, the information present in the mail are insufficient, and so the mail notification is of limited use.
We want to provide customization of the mail text and subject using mail text functionality, adding to the request type the mail template to use.
Additionally, the mail notification generated when a request is modified will not be sent to the user performing the modification.

[FreePath]

ADEMPIERE-49 on JIRA